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95th Percentile Current Speed [m/s]

Estimated extreme current speed, outlier-tolerant and comparable across sites for reconnaissance-level assessment

Description

95th percentile of the maximum current velocity magnitude across the water column calculated over the 1-year hindcast period, representing a robust, outlier-tolerant estimate of extreme current conditions at any depth under free-stream (undisturbed) conditions. This metric is intended for IEC 62600-201 [@iec_62600_201] Stage 1 reconnaissance-level analysis to provide a consistent basis for comparing extreme flow conditions across sites. It serves as a key input for initial structural loading assessment of turbine blades and towers, as well as for sizing electrical generation components and power electronics.

Equation

\[ U_{95} = \text{percentile}(95, \left[\max(U_{1,t}, ..., U_{N_{\sigma},t}) \text{ for } t=1,...,T\right]) \]

Where:

  • \(U_{i,t} = \sqrt{u_{i,t}^2 + v_{i,t}^2}\), velocity magnitude at sigma layer \(i\) at time \(t\) \([\text{m/s}]\)
  • \(\max_{\sigma}\), maximum value across all 10 sigma layers at each timestep
  • \(P_{95}\), 95th percentile operator over the full time series
  • \(N_{\sigma} = 10\), sigma layers
  • \(T\), 1 year of hindcast data (hourly for Alaska locations, half-hourly for others)

Properties

Property Value
Internal Name vap_water_column_95th_percentile_sea_water_speed
Units m/s